Collective Micro-Optics Technologies for VCSEL Photonic Integration

Table 1

Summary of main approaches proposed in the literature for integrating microlens on VCSEL devices. The three last columns concern polymer-based technologies.

Integration method	Hybrid assembly	Monolithic integration	UV photolithography	Replication	NIR self-writing
Lateral alignment precision	~2-3 μm (flip-chip~1 μm)	~1-2 μm; (Top-oxidation = self-aligned)	~1 μm	~1 μm	Self-aligned
Vertical positioning	Controlled by spacer and adhesive thicknesses	Controlled by semiconductor process fabrication	Controlled by spin coating conditions	Controlled by molding conditions	Controlled by exposure conditions
Wafer-scale process	No	Yes	Yes	Yes	Yes
Applicable after packaging	Yes	No	No	No	Yes
References	[2, 16–21]	[14, 26–31]	[3, 4, 34–36, 44, 46]	[38, 42]	[48]